Rearend narrowing question.

[tazzman68]

Is there a formula for figuring out what width of rearend you need when tubbing a vehicle?

[NATHANHASNORIDE]

I have also wandered this?I thought maybe you subtract however many inches your adding to the width of your wheels from the rear end.But that seems to simple to work so if anyone knows please let us know!

[tazzman68]

I know it has got to do with wheel width and offset. I suppose i could figure it out, i was just hoping that maybe someone had a foolproof way of figureing it out.

[GT-Racer]

if you know your wheel and tire combo already, you can set them under the truck where you want them to be, then measure between them from the mounting surface of each wheel.
That way you can get the wheels exactly where you want them in the wheel wells. This sounds like it would work, just my opinion tho as I have never done it, But I did stay at a holiday inn express last night.

[Pro-Street/StateTk]

Well as for a formula I have not came up with one, what I would do is start with a blank sheet of paper maybe get you a note book so you can record your measurements . Start measuring wheel lip to wheel lip inside where the lip rolls,then measure the frame, write down measurements allways measure twice, now back to the rear end housing I like to know the measurements from axel flange to axel flange, I also like to get brake backing plate to brake backing plate, then you will need to know the measurements of axels you will have a short side and a long side when I ordered axels for my drag car I measured probably 10 times and they did not come out right every time but when it came time to order them they were perfect! On the 77 Pro-Street ford truck I built I did not narrow the rearend I had a set of wheels made that dish to the inside about 11 inches and look stock from the side.

Your formula would be to start out asking your self lots of questions!

1. do you want the wheels dished deep from the out side of the truck or do you want the wheel center to be offset in the middle of the wheels?

2. what wheels you plan on using what offset some wheels have a much more rear wheel offset when others you can get them with a 3 1/2 backset

3. how much you want to spend on axels, know what spline you want before ordering.

4. if you narrow a lot you will have to tubb the bed

5. are you going 4 link, ladder bar, or move leafs inboard,

6. Street axels or drag racing axels

These are most or the things you will need to know. Summit and others have the housing ends to weld right in. Get a plan!